Large Area High Density Sub-20 nm SiO₂ Nanostructures Fabricated by Block Copolymer Template for Nanoimprint Lithography

We developed simple fabrication methods to effectively transfer the block copolymer nanopatterns to a substrate material. High aspect ratio, sub-20 nm nanopillar and nanohole structures are successfully fabricated in a SiO(2) layer in large area format, and the versatile utilities of these nanostructures as nanoimprint molds are studied. Nanoimprint lithography using these molds makes it possible to easily replicate densely packed block copolymer nanotemplate patterns on arbitrary substrates in a short processing time by using a large variety of polymer materials, including functional materials such as conjugated polymers. In addition, the PDMS soft stamps with both nanohole and nanopillar pattern polarities, which are useful tools for soft lithography and transparent template applications, are also successfully fabricated using the pillar- and hole-type SiO(2) molds. These soft stamps provide an effective way to fabricate controllable as well as reproducible plasmonic metal nanostructures with tunable surface plasmon resonances.